Pneumatic gate actuating device for concrete buckets



Oct. 14, 1958 w. T. GOSSETT ETAL 2 PNEUMATIC GATE ACTUATING DEVICE FORCONCRETE BUCKETS Original Filed May '7, 1949 JOHN 0. GOSSETT, &

WILL/E 7: GOSSETT,

INVENTORS.

HUEENE/P. BEEHL ER.

A TORNEVS. B

baa 1.4. Jul-Au.

WORREL HERZ/G. 8 CALDWELL,

United States Patent PNEUMATIC GATE ACTUATING DEVICE FOR CONCRETEBUCKETS Willie T. Gossett and John O. Gossett, Bridgeport, Wash.,assignors to Garlinghouse Brothers, Los Angeles, Calif., aco-partnership Continuation of abandoned application Serial No. 92,064,May 7, 1949. This application February, 15, 1954, Serial No. 440,020

(Filed under Rule 47(b)and 35 U. S. C. 118) 1 Claim. (Cl. 294-71) Theinvention relates to pneumatic motors and more particularly a systemadapted to the control of reversible pneumatic motors whereby the motormay be operated in a forward or reverse direction through control of asingle supply line through which pneumatic pressure is conducted to themotor. The system is most effective under circumstances where thepressure of the pneumatic supply for operating the motor in onedirection can be greater than the pressure of the pneumatic supply foroperating the motor in a reverse direction.

In the art relating to fluid motors it has been common practice toutilize double acting cylinders, whether hydraulic or pneumatic,whenever both forward and reverse motion is needed as a result of theoutput of the hydraulic or pneumatic motor. Obviously for the operationand control of double-acting motors of this kind two supply lines underpressure are necessary, one for the forward motion and one for thereverse motion. Obviously also there must be a control for both linescapable of syn chronization so that when one supply line is turned onthe other supply line is turned off and vice versa. Although verysatisfactory control is possible with fluid motor operating in thismanner the equipment in the nature of supply lines and valves must bedoubled in every instance. Moreover, there is a certain amount of delayin the reaction of the motor when the shift is made in the valvesettings from forward motion through a neutral position to reverse. Oncertain occasions there is a material advantage in a very rapid responseof the motor to operation in a reverse direction and there is under allcircumstances a great advantage reducing the number of fluid pressurelines and valves both from the point of view of minimizing the number ofmoving parts and reducing the cost. Although air brake systems maysuggest a variation from the double line expedient the fact that theymust be maintained under pressure demands expensive piping and heavyvalves accompanied by control tanks. Such systems are suited only tovery specialized requirements where small movement of the piston willperform the work and where reverse operation at all stages and at anytime is not demanded.

It is therefore among the objects of the invention to provide a new andimproved reversible pneumatic motor which is quick in its response toeither forward or reverse operation and which at the same time issubstantially less costly than motors heretofore devised for bothforward and reverse operations.

Another object of the invention is to provide a new and improvedconcrete placing bucket operated by a reversible pneumatic operatedmotor which is especially responsive to operation by use of air as apressure medium and wherein the gate of the bucket can be operated inboth opening and closing directions by manipulation of a single pressuresupply line incorporating a single three- Way valve.

Still another object of the invention is to provide a new 2,856,222Patented Oct. 14, 1958 and improved concrete placing bucket operated bya reversible pneumatic motor which can be eificiently and quicklyshifted from opening to closing operation and from closing operation toopening operation at virtually any point within the extremes of open andclosed position of the gate and which is economical from the point ofview of power consumption as well as from the point of view ofminimizing the amount of piping and valves necessary for completeoperation of the device.

Still further among the objects of the invention is to provide a new andimproved concrete placing bucket operated by a pneumatic ram and acontrol system therefor wherein by use of a single air supply line and areservoir connected thereto the ram can be operated in one direction atone pressure head and in the opposite direction under a pressure headdifferent from the first pressure head but still of sufficient magnitudeto produce the desired results.

An important object also is to provide a pneumatic motor device for bingates wherein the force required for opening is prone to vary over widelimits due to particles jamming the gate, whereby when the forceresisting opening movement is suddenly released the pneumatic motor willnot suddenly shift the gate to extreme position but will maintain asteady cushioned force whereby there may be maintained a relativelysteady but gradual progress to a full open position.

With these and other objects in view, the invention consists in theconstruction, arrangement and combination of the various parts of thedevice whereby the objects contemplated are attained, as hereinafter setforth, pointed out in the appended claim and illustrated in theaccompanying drawings.

In the drawings:

Figure 1 is a side elevational view partially in section showing thepneumatic motor and appropriate control system in use for operatinggates at the bottom of a hopper.

Figure'Z is a schematic view of the pneumatic motor and control systemillustrating the principle of operation and applicable to producing anyopening and closing movement.

This is a continuation of our co-pending application Serial No. 92,064,filed May 7, 1949.

The embodiment of the invention described herein involves the control ofgates at the bottom of a concrete hopper. In the instance shown thehopper is one commonly identified as a portable concrete bucket which isadapted to be loaded,lifted and emptied in any position desired andreturned at will for reloading. Requirements,

number of working parts is of a very material advantage when the deviceis to be used successfully in the field. As shown in the drawings thereis disclosed a portable concrete bucket comprising a frame 10 includinga lower rim 11, an upper rim 12, a bin, hopper or hollow container 13and brackets 14 at the upper rim 12 having apertures 15 therein to whichmay be attached a cable sling for lifting the device about.

In the embodiment illustrated the hopper has a lower opening at thepoint 16 which in this example is illustrated as being closed by a pairof clamshell gates 17 and 18 which rotate to and away from each other inresponse to the power mechanism comprising the invention. For effectiveoperation the clamshell gates may be provided with rounded plates 19 and20 having edges 21 and 22 which close tightly against each other whenthe opening in the bottom of the hopper is to be cotn-.

pletely closed. Furthermore in this embodiment the gates are providedrespectively with segmental gears 23 and 24 intermeshing with each otherand rotating respectively about shafts 25 and 26. The gates are normallyurged toward each other in a closed position by means of a heavy tensionspring 27.

For manipulating the gates a bracket arm 28 is attached to the gate 18and by shifting the bracket arm in an oblique direction up and down bothof the gates are moved simultaneously toward an opening or closingposition.

The power system for operating the gates in the embodiment illustratedincludes an air motor or ram 35, which is here shown as a hollowcylinder, having a bracket 36 by means of which the ram is attached to asupport 37 comprising part of the frame 10. The point of attachment ispreferably by means of a pivot 33 so that the ram is free to swing acertain limited angular distance about the pivot.

Within the ram is a piston 39, shown schematically in Figure 2, andattached to the piston is a rod 40 including a packing gland 41 and anadjustable collar 42, the rod being attached by a pivot pin 43 to thearm 28.

A main supply line for air under pressure is shown at 44 and this lineis preferably a flexible line anchored by means of a fitting 45 to theframe it). An extension 46 of the main supply line is shown joined to aT47 joined by a length of line 48 to a fitting 49 at one end 50 of theram 35.

A closed air container or pressure reservoir 51 is shown attached bymeans of a strap 52 to the frame and an auxiliary supply line 53 isconnected between the T47 and the reservoir. A check valve 54 isincluded in the auxiliary supply line 53 and prevents air under pressurefrom passing through the auxiliary supply line 53 in a direction reverseto the arrow illustrated in Figure 1.

From the reservoir a secondary, counteracting or reverse supply line 55extends to a fitting 56 connected to the end 57 of the ram remote fromthe end 56. In the counteracting supply line there is included apressure regulating or pressure reducing valve 58 here shown locatedimmediately above the reservoir, a check valve 59 here shown locatedimmediately adjacent the fluid regulator and a pressure relief orpop-off valve 64) shown located between the pressure regulator and theram or more especially between the check valve 59 and the ram.

As is more readily apparent from an examination of the schematic diagramin Figure 2 pneumatic pressure may be supplied by means of a pump 65through a primary line 66 to a three-way valve 67 provided with acontrol 68. This valve may be of conventional construction such as apiston and cylinder which is capable of being set at any one of threepositions, namely, a position connecting the primary line 66 with themain supply line 46, a position neutral wherein the main supply line 46is entirely shut off and an exhaust position wherein the main supplyline 46 is exhausted to the atmosphere. For convenience there may beprovided in the main supply line 46 a quick disconnect coupling 69. rThe main supply line may also preferably include a filter 70, the latterbeing also shown in Figure 1.

In operation the system herein described may be utilized to either openor close the clamshell gates 17 and 18. Assuming the initial position ofthe gates to be closed, as illustrated in Figure l, the next operationof the device may be considered as an opening movement for the motor orram 35. To open the gates the valve 67 is adjusted to open position, aposition wherein pneumatic fluid pressure from the primary line 66 isallowed to pass to the main supply line 46 which in turn directlysupplies the line 48 connected to the end 50 of the ram 35. If, forexample, the pressure be pounds per square inch,-then the pressureagainst the piston 39 will be of the magnitude of 100 pounds per squareinch and the piston will be moved from a lowermost position asillustrated in Figure 2 to an uppermost position as there ilustrated. Amotion in this direction of the piston and the attached rod 46 serves toshift the position of the arm 28 thereby moving the position of thegates to successive opening positions for as long as the valve 67remains open. If no further adjustment is made in the valve 67 theopening movement will continue until the piston 39 bottoms against theend 57 of the ram.

In the meantime fluid pressure from the main supply line 46 is likewisepermitted to pass through the check valve 54 into the fluid pressurereservoir 51 thereby building up a fluid pressure of, in the examplechosen for the purpose of illustration, 100 pounds per square inch. Thereservoir is made in suflicient volume so that fluid therein under apressure equal to the pressure in the main supply line 46 is capable offilling the cylinder of the pneumatic ram 35. When reference herein ismade to a fluid it is directed to a compressible fluid, air being thefluid most readily available.

In the counteracting supply line 55 the pressure regulating or reducingvalve 53 is set for a pressure less than the pressure in the main supplyline 46 and for purposes of example let it be assumed that the settingis for a pressure of 30 pounds per square inch. By this device fluid isadapted at all times to pass from the reservoir 51 to the counteractingsupply line under a pressure of 30 pounds per square inch. The checkvalve 59 admits passage of fluid outwardly from the reservoir butprevents passage in a return direction. When the cylinder is being movedthrough an opening cycle there will of course be air, gas or other fluidunder a 30-pound pressure at the end 57 of the ram. As the piston 39moves toward the end 57 there will be a tendency to compress the air inthat part of the system where it is maintained by operation of the checkvalve 59. In order to relieve air thus compressed, the relief valve 60is set to release at a pressure of 30 pounds per square inch or slightlyhigher, and the action of the relief valve will, therefore, preventundue compressing of any gaseous medium in that portion of the systemduring a forward stroke.

It becomes immediately apparent therefore that there is always present afluid pressure at the end 57 of the ram but that the pressure at the end57 is always less than the pressure at the end 50 during the initialstroke.

This differential in pressures reduces the effective initial pressureupon the piston to a net pressure of the difiference between 100 poundsper square inch and 30 pounds per square inch in the example chosen,namely, 76 pounds per square inch. The net pressure will of course bechosen so that it is sufficiently great to efiiciently operate the gates17 and 18 in the embodiment shown or any other work element which may beattached to the piston rod 40.

Whenever the valve 67 is shifted to exhaust position, pressure in themain supply line 46 is immediately reduced to zero which means that thepressure at the end 50 of the ram 35 is also reduced to zero, or forpractical purposes zero gauge pressure. Inasmuch as the pressure at theend 57 of the ram 35 is already 30 pounds per square inch, also gaugepressure, there is immediately effective a substantial pressure on thecorresponding side of the piston 39 which is suflicient to move thepiston 39 and the piston rod 41} in a direction contrary to thedirection of the initial stroke. Movement of the piston in thisdirection will continue as long as the valve 67 stays in exhaustadjustment or if the piston 39 bottoms on the end 50 of the ram 35. Thepressure at the end 57 of the ram will never be greater than thepressure at which the regulator valve 58 is set so long as all of thedevices are in pro-per working order. If the regulator valve 58 gets outof adjustment, pressure in the counteracting supply line 55 will bereleased at the setting of the presneutral position.

sure relief valve 60. The wide pressure differential produces a strongpositive pressure in both opening and closing directions, cushionedagainst the high pressure movement and wherein the ample volume of airassures a long stroke in both directions.

There are, however, occasions where it may be desired to stop movementof the piston 39 intermediate the extremes of position. When this isdesirable it is neces sary only to shift the adjustment of the valve 67to a In this position no more fluid under pressure will be admitted tothe end 50 of the ram 35 and the piston 39 will therefore remain stillfor as long as the adjustment continues. From still position the piston39 may be moved either further in the initial direction by againshifting the valve 67 to open adjustment or it may be reversed byshifting the valve 67 to exhaust adjustment. Whenever the valve 67 ismoved to exhaust adjustment the pressure of 30 pounds per square inchwhich is always present in the end 57 of the ram 35 will becomeimmediately effective to move the piston 39 toward the end 50. Thesensitiveness of the fluid motor to reversal in direction thereforebecomes immediately apparent. By the system thus described, therefore,both forward and reverse direction can be achieved by a single actingfluid motor by manipulation of the single valve control. On someoccasions, as for example in the embodiment illustrated, the weight ofthe gates assists in the closing movement wherein less pressure isavailable in the ram 35 than during the opening movement. Other uses ofthe system, however, may not necessitate amplifying or assistingmovement of the operating portion of the fluid motor in a reversedirection. Moreover, by use of a system of this kind, particularly whenadapted to the control of the gates of a portable concrete bucket, onlyone pressure supply line need be attached between the pump and the fluidmotor. This is particularly helpful when it is realized that buckets ofthis kind may be lifted to considerable heights away from ground controland supply and to make possible the successful operation by the use ofonly one pressure line instead of two results to a very material degreein the reduction of weight and quantity of necessary parts. It alsogreatly facilitates the operation and movement of the device since onlyone supply line or hose need be carried about and around obstructionswhich are almost always present when the device is operated in thefield. Reduction in the number of working parts in the presentembodiment also reduces the weight of elements which have to be carriedupon the frame which bears the hopper and the gates and this results inan additional economy both from the point of view of initial weight andfrom the point of view of weight which needs to be shifted about whenthe device is in operation. The advantages of the simplified systemherein described are equally great when the fluid motor and controlsystem is applied to many other types and varieties of work whether thework may be portable or stationary and whether or not the piston rod beheld stationary with the ram adapted to be movable or under reverseconditions like those illustrated in the embodiment shown in Figure 1.

An outstanding advantage of this control system is that at all timeswhen operating by use of compressed air the maintenance of a backpressure against the piston 39 during a forward stroke provides asmooth, controllable motion for the piston. This control is in contrastto the jerky uncontrollable motion invariably present in an air cylinderoperating a device such as a bin gate on which the force reguired toopen the gate varies. This condition is true of virtually all bin gatesparticularly where a granular substance is being discharged. Under suchcircumstances particles of the granular substance are prone to be caughtbetween the sliding gate portion and the body of the gate, therebytemporarily increasing to a great amount the force required to move thesliding gate portion until these small particles are forced out ofposition. The instant such particles are forced out of position and thepressure against the sliding gate portion relieved, the force requiredto move the sliding gate portion is materially reduced. At that point inthe ordinary air cylinder the built-up pressure in the piston will causethe piston to jump and open or close the gate to its extreme position.In the system herein described, wherein there is always a constant backpressure against the piston while it is moving in the gate openingdirection, there is practically no jump in the piston when the forcerequired to open the gate is suddenly reduced. Although this cushioningeffect may not be present in the arrangement disclosed when the gate isbeing closed, in practically all operations of this general sort thequicker the gate is moved to a closed position, the more effective isthe operating system.

While we have herein shown and described our invention in what we haveconceived to be the most practical and preferred embodiment, it isrecognized. that departures may be made therefrom within the scope ofour invention, which is not to be limited to the details disclosedherein but is to be accorded the full scope of the claim so as toembrace any and all equivalent devices.

Having described our invention, what we claim as new and desire tosecure by Letters Patent is:

In a bucket for depositing concrete having a frame, a bottom openinghopper in the frame and a pair of oppositely opening and closing clamshell gatees rotatably mounted on the frame in interconnectedrelationship one gate with the other, the combination of a pneumaticgate opening and closing system comprising a cylinder mounted on theframe, a reversible piston in the cylinder having a piston rod extendinginto engagement with one of said gates, a flexible high pressure airline having one end secured to the frame and having an operating valveat the other end, said valve being remote from and unconnected to theframe and having open, neutral and exhaust positions, means on saidvalve for connection to a source of air under pressure, an air storagetank on the frame, said air line having one branch on the frameconnected directly to the cylinder at a high pressure end and havinganother branch connected to the tank, said last identified branch havinga back flow check comprising the only air control means between saidvalve and the tank, and a continuous free-flowing lower pressure airline from the tank directly to the cylinder at a lower pressure endthereof, a continuously open pressure regulating device in said lowpressure air line having a pressure setting at substantially one-halfthe pressure in the high pressure air line and a relief valve in saidlow pressure air line between the regulating device and the cylinderhaving a pressure release setting substantially equal to the setting ofsaid pressure regulating device, said operating valve having agate-opening adjustment at open position and a gate-closing adjustmentat exhaust position.

References Cited in the file of this patent UNITED STATES PATENTS

